As the infrastructure of the United States and the world continue to age and deteriorate, the need for solutions to infrastructure problems increases. One key infrastructure component that requires considerable rehabilitation or replacement is pipelines for transporting water, sewage, oil, and gas. Several problems persist regarding existing pipe infrastructure; including age, improper installation, decentralized planning of piping systems, inadequacy of rehabilitation techniques, and high cost of replacement.
One of the underlying problems with existing pipes, especially sewer pipes, is that many were made and installed long ago and oftentimes were assembled with pipes of varying diameters as new developments were incorporated into the system. Additionally, due to the old age of the pipes, as well as the materials used to make them, many pipes have begun to deteriorate, deform, or have damaged areas. The deformed or damaged areas create weak spots, which may allow water, roots, and dirt to infiltrate the sewer system and also lead to the eventual collapse of the pipe.
Methods exist for repairing the walls of pipes and other conduits. One such method involves the use of a cured-in-place (CIP) liner with a polymer coating on its interior surface and a bladder to repair the pipe wall. The liner is impregnated with a resin capable of curing and hardening. The liner and bladder are placed in the pipe, and the bladder is inflated to press the liner against the pipe wall. The resin is allowed to cure and harden, creating a new interior pipe wall. Since many liners include an interior polymer coating impervious to a resinous material, the liners usually cannot fold over themselves or bunch up because the liner wall would be formed with intermediate layers of material impervious to resin causing the liner to not be homogeneous across its thickness. The completed lining will be uneven and obtrusive within the pipe, disrupting pipe flow and allowing clogs to occur within the system.
One problem with existing methods of CIP lining is that the methods do not conform well to pipes with variable inner diameters. The common methods call for the use of a CIP liner and bladder having a diameter approximately equal to the diameter of the pipe. However, some pipes may include a plurality of diameters across their length due to decentralized planning of the sewer system or pipe deformation. There are two methods currently available to address this issue in CIP lining. The first includes lining the length of pipe in several segments, where a plurality of liners having diameters that match the pipe diameter are installed successively until the entire length of pipe has been lined. This method is extremely time-consuming in the field and may result in an uneven lining with the possibility for cold joints at the liner junctions. The second method commonly employed is tailoring a liner in a manufacturing facility to meet the exact dimensions of the length of pipe to be lined. This process is time-consuming and labor-intensive from a manufacturing perspective.
If an undersized liner were to be used to address such a problem, several problems would arise. It is conceivable that the use of a CIP liner having a diameter approximately equal to the smallest diameter of the pipe with the liner being capable of stretching circumferentially to press against the pipe wall so to prevent the liner from wrinkling could be a feasible option to repair a pipe length having a plurality of inner diameters. However, the process of using such pipe liners may require that the liner stretch considerably to repair the entire length of pipe. This can cause the liners to rip, tear or be too thin, leaving the pipe wall not fully repaired. Additionally, circumferential stretch of a fabric liner will usually result in loss of length. In such cases, it is uncertain whether the lining will cover the entire length of pipe to be repaired.
Accordingly, there is a need in the art for an improved method and means that overcomes the problems of obtrusions and irregular wall thickness in CIP pipelining applications. There is also a need in the art to provide an alternative to the time-consuming and labor-intensive process of producing pipe liners tailored to fit transitions in pipe diameter in a length of pipe.